The present invention relates to thermoelectric pipe fittings for connecting pipes.
Pipe fittings are known in which an electric winding incorporated into a heat-fusible material is buried. Once the pipe end made of the same heat-fusible material as the pipe fitting has been inserted into the pipe fitting itself, for making a connection it is sufficient to cause running of a predetermined electric current through the winding. This gives rise to heating of the heat-fusible materials of the pipe fitting and the pipe. Thus the inner surface of the pipe fitting and outer surface of the pipe are melted together, thereby accomplishing a steady sealing.
Obviously, this connecting technique can be adopted only if the materials forming the pipe and pipe fitting are the same and suitable for heat-melting. When the materials are not identical, traditional systems involving a mechanical coupling are to be employed.
Due to the above, use of thermoelectric connecting methods is excluded or greatly complicated with many materials having very interesting physico-chemical characteristics for making ducts and pipe fittings having particular features. For instance, well known are plastic materials having excellent features in terms of resistance to aggressive fluids such as hydrocarbons, but of difficult or impossible heat sealing with materials such as the polyolefin-based ones, polyethylene for example.
For example materials resistant to hydrocarbons having interesting features but incapable of being heat-sealed to polyethylene are aliphatic polyketone having a perfectly alternate structure, polyamides, alloy of polyamides. The general object of the present invention is to eliminate the above mentioned drawbacks by providing a pipe fitting that, by electric heating, enables a pipe and a pipe fitting to be steadily and sealingly connected, even if they are not made of materials heat-sealabling to each other.